In-depth research on percarbonate expediting zero-valent iron corrosion for conditioning anaerobically digested sludge

Simultaneously Enhanced Dewaterability and Biopolymer Release of Sludge by Natural Deep Eutectic Solvents: Performance, Mechanisms, and Insights of Theoretical Calculations

“…51 Two peaks identified at 168.9 and 163.7 eV were assigned to the −SO 3 and S−S bond, respectively. 52 As shown in Figure 7, there was a slight increase of protein-N after thermal treatment only, and similar results were also reported with thermal treatment. 53 However, the contents of protein-N in sludge remarkably decreased from 85.60% (control) to 75.58 and 66.51% after N and NH conditioning.…”

“…In addition, from the S 2p spectrum of XPS (Figure S6), we found that the percentage of disulfide bond groups decreased from 54.02 to 36.91 and 39.7% after N and NH treatment, respectively. This indicated that NADES pretreatment may also lead to disulfide bond (S–S) cleavage and further alter the conformation of proteins from EPS . The decline of C–(C, H) (C 1s) from 63.2 to 53.9%, and CO (O 1s) from 54.7 to 44.1% were also observed after NH treatment, further showing that AAs, lipids, and polysaccharides were detached from the sludge surface.…”

“…The N 1s peak at 400.0 eV correlated with protein-N, and the other N 1s peak at 401.5 eV is commonly associated with inorganic-N, while the O 1s signal included two peaks at 532.5 and 531.5 eV, which are attributed to CO (proteins/polysaccharides) and C–OH/C–O (glycoside), respectively . Two peaks identified at 168.9 and 163.7 eV were assigned to the −SO 3 and S–S bond, respectively …”

“…This indicated that NADES pretreatment may also lead to disulfide bond (S−S) cleavage and further alter the conformation of proteins from EPS. 52 The decline of C−(C, H) (C 1s) from 63.2 to 53.9%, and C�O (O 1s) from 54.7 to 44.1% were also observed after NH treatment, further showing that AAs, lipids, and polysaccharides were detached from the sludge surface. In general, the analysis of surface functional groups reveals that NADES effectively breaks the EPS structure and thus improves the sludge dewaterability.…”

Enhancing Methane Production from Anaerobic Digestion of Waste Activated Sludge through a Novel Sodium Percarbonate (SPC) Pretreatment: Reaction Kinetics and Mechanisms

“…Besides, it should be noted that no extra Fe was dosed and the initial pH for SPC activation was not adjusted. In contrast, the SPC used for sludge disintegration was activated under strongly acidic (pH = 3) conditions with the addition of 20 mg/g Fe (II) or 200 mg/g TS zero-valent iron (ZVI), which would bring about higher costs because of the pH adjustment and extra Fe addition. , Therefore, the costs for SPC activation in this study would be much saved. In addition, the pretreatment for SPC oxidation could be performed within 24 h, which implied that the SPC-based technology could incur more efficient sludge pretreatment compared to other strategies such as CaO 2 , KMnO 4 , etc. , …”